The present invention relates to a roofing panel assembly made of mutually adjacent modular roofing panels.
In the art it is known how to effect splicing of roofing panels or other modular roofing elements for covering flat or fret-shaped roofs by a notch and overlap method to ensure continuity of the roof covering between one roofing panel and the other, thereby preventing infiltration of rainwater at least in the roof's standard operating conditions. However, with the conventional flat or fret-shaped roofing elements, when the water level in the collecting and discharge channels delimited between adjacent roofing elements exceeds the top level of a vertical leg in the locks, the roof leaks.
This can occur in a number of occasions, e.g. owing to heavy rainfall which obstructs the channels, to rain combined with wind in which case water is driven above the level of the vertical rib in the locks, to a high ratio between the length (L in meters) and the inclication (I in percentage) of the pitches of a roof, e.g. L/I&gt;2, to abundant hail which fills the channels between the roofing elements followed by rain, so that all the water cannot be drained away, and thus its level rises, and to melting snow, which may restrict or prevent water draining, especially at the front end of the roof pitches, where thaw is delayed.
It has already been suggested to provide various types of sealing along the roofing element overlaps, but the problem of water infiltrations has not been satisfactorily solved since thermal expansion and contraction movements and unavoidable aging of the sealants, at least in the long run, inevitably cause leakages.